Such a ban (exceptions would be made for emergencies) would go far beyond what states now have in place. Currently, no state has a ban on all cellphone use by all drivers, according to the Governors Highway Safety Assn., although some prohibit cellphone use by certain drivers.

Novice drivers are banned from using cellphones while driving in 30 states and the District of Columbia. School bus drivers can't use cellphones in 19 states and D.C. when they have passengers. States are tougher on texting while driving: 35 plus D.C. ban the practice.

In the Missouri incident in August 2010, about 50 students, mostly from a high school band, were headed to a Six Flags park when they were part of a pileup that, the NTSB says, was caused by a 19-year-old driver who sent or received 11 texts directly before his pickup hit the back of a tractor truck.

One school bus then slammed into the pickup, riding up over the smaller vehicle, according to the Kansas City Star. Then the second bus rammed into the first. The pickup driver and a 15-year-old on one of the buses died.

The NTSB can't force states to ban cellphone use by drivers, but the Associated Press notes that its recommendations carry weight with federal and state officials.

Among other cases the NTSB has investigated: In Chatsworth, 25 people died in a 2008 train collision involving texting by an engineer.

NTSB Chairwoman Deborah Hersman last year called the texting by engineer Robert Sanchez "egregious." The contracted Metrolink engineer had been counseled about the issue before the wreck, she said, but continued "in a pattern of behavior that was unsafe on a regular basis."

Then there was a fatal accident in July 2010 on the Delaware River near Philadelphia. A tugboat pilot who was using his cellphone and laptop crashed into a sightseeing "duck boat." More than 30 tourists on the small vessel fell overboard, and two of them died.

Last month, the tugboat's captain, Matthew Devlin, was sentenced to one year and one day for misconduct of a ship operator causing death.

He had pleaded guilty to the crime. He said in court, according to Reuters: "I just wish I could take it all back."